Respiratory appliance



C. VON HOFF @szi. 1%, 1948.

AIPLI'ANCE Original Filed Nov. 15, 1935 Patented Oct. 8, 1940 V UNITEDSTATES PATENT OFFICE nnsrmn'roav APPLIANCE Carl von Hofi, Essen,Germany, assignor to Otto Heinrich Drager, Lubeck, Germany ber 14, 19349 Claims.

This is a division of my co-pending application No. 49,981, filedNovember 15, 1935.

This invention relates to respiratory appliances having circulation ofthe respiratory air and automatic lung-controlled oxygen feeding.

In respiratory appliances of this kind, arrangements are known foravoiding excess of nitrogen. The arrangements aim at the passa e or" asuiflcient quantity of nutritive gas or oxygen whilst 10 avoiding theconstantly uniform nutritive gas feeding which considerably shortens theduration of use of the appliance, and which is mostly provided inaddition to the automatic lung-controlled feed.

In order in a respiratory appliance having automatic lung-feeding, toadapt the supply of oxygen exactly to the demand at any time, therespiratory appliance is, in accordance with the invention, connected toan intermediate container of variable volume and maintained continuouslyunder regulated pressure of the oxygen so that every movement of thewall of the respiratory bellows is mechanically transmitted andwhichcontainer is also connected with the respiration bellows by means of aconnecting member adapted to introduce the oxygen into the bellows andhaving a force closure control. so that on each increase of volume,oxygen passes from the storage container into the intermediate containerandon each diminution of volume, oxygen is pressed out oi the containerinto the respiration bellows. In order not to render more difllcult themovement of the wall of the respiration bellows by means of the pressureof .the

oxygen inside of the intermediate container, pressure compensating meansmay be provided; for example, a movable bottom or piston whichsubdivides the container, is actuated by lever transmission and has adouble contacting action, a

spring member operating in opposition to the oxygen pressure, or thelike;

The respiration bellows is in general larger than the intermediatecontainer connected to it. The ratio of the dimensions taken inconnection with the position oi. the parts with regard to one another isso chosen that the quantity of respiration air in the bellows has acertain amount of oxygen, for example, about 440% added to it. Theintermediate container is during the employment of the appliance,incontinuous direct connection with the reducing valve of the oxygencontainer, which may be, for example, adjusted to a pressure of 100 mm.water column. If, during the inspiration, the volume of the respirationbellows decreases, then with the corresponding diminution of theintermediate container, the oxygen located therein must pass overthrough the connection provided into the respiraamounts to mm. watercolumn, then a coun- 15 I ter pressure on the valve in the connectingconduit of about mm. will suflice for closing it.

For the respiration bellows in appliances according to the presentinvention, bellows of concertina-like type having a fixed lower wall anda movable but rigid upper wall, are particularly suitable. Bellows ofthis kind have a volume and a variation of volume which can be easilydetermined-which fact is important in connection with the presentappliance for the reason 25 that the oxygen supply is dependent on thevariation of volume of the respiration bellows. Furthermore thesebellows render possible easy transmission of the movement of theirwalls. If the transmission of the movement is efiected by 30 means of aone or two-armed lever, then the power necessary for the alteration ofvolume can be diminished by the alteration of the point of connection ofthe intermediate container with the short lever arm. This power is alsoin any 35 case less on account of the smaller volume of the intermediatecontainer as compared with the respiration bellows. The oxygen pressureexisting in the intermediate container facilitates the expansion of therespiration bellows and thereby 4o diminishes the resistance of the wallof the bellows during the expiration. II, as is provided for, the oxygenpressure in the intermediate container is eliminated by means of acompensating arrangement, then the alteration of volume of the inter- 45mediate container does not cause any overload during the movement of thewalls of the respiration bellows. The force for opening the valve in theconnecting conduit can be completely eliminated by the transmissionratio of the long lever 50 arm to the short one. I

The advantage oi. the intermediate container as a. measuring deviceresides, as compared with the known arrangements, in the fact that theconducting path for the respiration air remains as whole pressure of theoxygen containe but, by

the direct connection of the reducing valve with the intermediatecontainenthe supply of oxygen is in the first place limited to thecapacity of the latter and the quantity of oxygen passing out of theintermediate container into the conducting path is limited'totheparticular amount which is determined by the alteration of volume of therespiration bellows.

In order that the invention may be fully understood, some embodimentsthereof will now be described by way of example by reference to theaccompanying drawing in which the figures of the drawing are restrictedto that part of a respiration appliance which is necessary for thecomprehension of the invention. The drawing shows in:

Fig. l, the mechanical and pneumatic connection of the respirationbellows with an intermediate container subdivided by means of a movablebottom, and the always open connection of the latter with the reducingvalve of the oxygen container,

Figs. 2-4, the same connection with a singlespace intermediate containerwith various means for the transmission of the movement,

Fig. 5, a tension spring in the interior of the intermediate container,and

Fig. 6, a compression spring above the intermediate container acting asa compensation for the oxygen pressure.

According to Fig. 1, the intermediate container b is provided with apressure compensating means consisting of a movable intermediate bottomd,

which is connected with the two stationary boundary walls after themanner of a concertina. Into each of the two boundary walls, a branch orthe conduit 0 to the reducing-valve c opens, so that both halves of thecontainer b are under the same oxygen pressure. By means ofthetwo-armedlever 9 adapted to swing on thestationary fulcrum f,themovement of the wall of the respiration bellows a is transmitted to themovable intermediate bottom d of the containerab. During this movement,

the intermediate bottom (1 presses the oxygen alternately out of thelower and upper container half I) through the conduits c which arelikewise connected to the two boundary walls of the container, theoxygen passing either directly or indirectly into the respirationbellows a. As a consequence of the fact that the bottom d is operatedupon by the oxygen on both sides, the pressure in the intermediatecontainer above and below the bottom 11 is compensated. For the movementof the bottom d, only the power required for opening the valve :0 in theconnecting conduit 0 is consequently necessary. If, for example, theoxygen pressure in the intermediate container amounts to mmQand the loadof the valve 1: to about 20 mm. more, then there is opposed to thetransmission of movement of the respiration bellows to the intermediatecontainer only the small pressure of 20 mm., which, however, is almostentirely eliminated by the arrangement of the intermediate bottom d onthe short lever arm. The magnitude of the movement of the intermediatebottom (1 and consequently the alteration of volume of the container 1),can be adjusted by providing on the short arm of the lever g a number ofbores,

wherein a variable positioning of the bottom-811s rendered possible. inthis embodiment in consequence of the subdivision of the intermediatecontainer'i), the oxygen therefrom is pressed into the respirationbellows, not only when the latter contracts, but also when it expands.

In the embodiment shown in Fig. 2, the transmission of motion from therespiration bellows a to the intermediate container b is effected bymeans of the one-armed lever g fulcrumed at I, the point of applicationof the respiration bellows a being on the long lever arm, and the pointof application of the intermediate container b being on the short arm.In this case, the conduit 0 leads from-the intermediate container 1) tothe reducing valve 0, and the conduit c with the valve :0 leads to therespiration bellows a.

In Figure 3, the intermediate container b is arranged in the middle ofthe respiration bellows a. Both of these are retained in position so asto be movable by means of the common top wall. From the reducing valve 0the conduit 0 leads into the intermediate container b which is connectedwith the respiration bellows a by means of the connection 0 which iscontrolled by force closure.

In the embodiment shown in Figure 4, the respiration bellows a islocated after the manner of a wedge between two walls connected by ahinge f, the upwardly directed wall g being adaptedto swing and, owingto this capacity or swinging, produced by the alteration of volume ofthe respiration bellows a. effecting the alteration of volume of theintermediate container b. The container b, which is adapted to bearranged at any desired place between the two walls, is, in this case,illustrated as being located on the long lever arm. The intermediatecontainer b is also connected by means of the conduit 0 with thereducing valve 0 and by means of the conduit which is controlled byforce closure with the respiration bellows a.

Forcompensating for the oxygen pressure, there is provided, according toFigure 5, a tension spring arranged inside the intermediate container b,which spring, acting against the oxygen pressure, tends constantly todraw the movable top wall of the container downwards, whilst in theconstruction shown in Fig. 6, there is arranged above this movable topWall's. compression spring supported at its other end. It the powerdemand for compressing the intermediate container b exceeds thepermissible load on the lungs, which for example, may be the case in theem bodiments illustrated in Figs. 3 and 4, a compensating means of thiskind for the pressure is desirable. In an arrangement such as is shownin Figure 2, wherein the operating power for the intermediate containeris applied to the short lever arm, a pressure compensating means is notnecessary.

With the ipfle rmediate container b the variabilityof its volume isillustrated on the drawing by means of an intermediate bottom movedafter the manner of a concertina, or by a similarly moved top wall. Thesame object can be obtained by means of a bellows of another kind, or astationary hollow cylinder having a piston moved within it by the actionof the respiration bellows.

The position of the respiration bellows with the quantity meterregulating the oxygen supply is the same as is general with circulationappliances for the respiration bellows, for example, between pipe.

I claim;

1. In a lung controlled respiratory appliance having automatic oxygensupply, the combination of: a respiratory bellows, a source of oxygensupply, and an intermediate variable volume container in communicationwith said om-- gen supply source and said respiratory bellows in suchmanner as to allow of passage of oxygen from said source to saidcontainer and from said container to said bellows, and said containerbeing constantly positively operatively connected to the wall of saidbellows such that every variation in volume of said bellows.pro duce's aproportional variation in volume of said intermediate container, everyvolume increase of said container causing oxygen to pass from saidsource of supply to said intermediate container and every volumediminution thereof causing oxygen to be forced from said container intosaid bellows in an amount which is a constant uniform percentage of theair respirated.

2. In a 'lung controlled respiratory appliance having automatic oxygensupply, the combination of: a respiratory bellows, a source oi oxygensupply; an intermediate variable volume container in communication withsaid oxygen supply source and said respiratory bellows in such mannerasto allow of passage of oxygen from said source to said container andfrom said container to said bellows; anda lever connected at one end tosaid container.and constantly responsively connected at the other end tosaid bellows for positively operatively connecting said container to thewall of said bellows such that every variation in volume of said bellowsproduces a proportional variation in volume of said container, everyvolume increase of said container causing oxygen to pass from saidsource of supply to said intermediate container and every volumediminution thereof causing oxygen to be forced from said container intosaid bellows in an amount which is a constant uniform percentage of theair respirated.

3. In a lung controlled respiratory appliance having automatic oxygensupply, the combination of a respiratorybellows, a source of oxygensupply, an intermediate variable volume container communicating withsaid oxygen supply source and said respiratory bellows in such manner.as to allow of passage of oxygen from said source to said container andfrom said container to said bellows and said container being constantlypositively operatively connected to the wall of said bellows such thatevery variation in volume .of said bellows produces a pro- .portionalvariation in volume of said interme diate container,- every volumeincrease of said container causing oxygen to pass from said source ofsupply to said intermediatecontainer. and every volume diminutionthereof causing oxygen to be forced from said container into saidbellows in an amount which is a constant uniform percentage of the airrespirated, and force closure means for preventing passage of oxygenfrom said container to said bellows except during movement of thelatter,

4. In a lung controlled respiratory appliance having jautomatic oxygensupply, the combination off [a respiratory bellows, a source of oxygensupply, an intermediate variable volume container, conduits connectingsaid container respectively to said oxygen supply source andto saidrespiratory bellows in such manner as to allow of passage of oxygen fromsaid source to said container and irom said container to said bellows,and said container being constantly positively operatively connected tothe wall 01 said bellows such that every variation in volume of saidbellows causes a proportional volume variation of said intermediatecontainer,"every volume increase of said container causing oxygen topass from said source of supply to said intermediate container and everyvolume diminution thereof causing oxygen to be forced from saidcontainer into said bellows in an amount which is a constant uniformpercentage of the air respirated,

r and a. valve disposed in the conduit connecting" said container tosaid bellows, said valve being held normally closed under the action ofa force, 15 such as a spring, greater than the pressure of the oxygen insaid container.

5. In a lung controlled respiratory appliancehaving automatic oxygensupply, the combination of: a respiratory bellows; a source of oxygensupply; an intermediate variable volume container communicating withsaid oxygen supply source and said respiratory bellows in such manner asto allow of passage of oxygen from said source to said container andfrom said container to said bellows; and a lever connected at one end tosaid container and at the other end to said bellows positivelyoperatively connecting said container the wall of said bellows such thatevery variati n, in volume of said bellows causes a volume vvariation ofsaid container, every volume increase of said container causing oxygento pass from said source of supply to said intermediate container andevery volume diminution thereof causing oxygen to be forced from saidcontainer into said bellows in an amount which is a constant uniformpercentage of the air respirated, and the point of engagement of saidlever with said container being variable for the purpose of controllingthe variation of volume of said container.

6. In a lung controlled respiratory appliance having automatic oxygensupply, the combination of a respiratory bellows; a source of oxygensupply; an intermediate container of variable volume communicating withthe'respiratory bellows'and the oxygen supply source; and a movablebottom subdividing said container, said bottom being operativelyconnected to the wall of said bellows such that every wall movement ofsaid bellows is transmitted to said ,bottom whereby'each expansion andcontraction of said bellows causes alternately the evacuation of oneside and the simul-' taneous filling of the other side of saidcontainer.

'7. In a lung controlled respiratory appliance having automatic oxygensupply, the combination of: a respiratory bellows; a source of oxygensupply; an intermediate variable volume container 5 communicating withsaid oxygen supply source and said respiratory bellows in such manner asto allow of passage of oxygen from said source to said container andfrom said container to said bellows; and said container being positivelyoperatively connected to the wall of said bellows; and a tension springdisposed within said container, said spring-normally tending to contractsaid container, the arrangement being such that every wall movement ofsaid bellows causes a volume variation of said container whereby onevery volhaving automatic oxygen supply, the combination or: arespiratory bellows; a source of oxygen supply; an intermediate variablevolume container communicating with said oxygen supply source and saidrespiratory bellows in such manner as to allow of passage of oxygen fromsaid source to said container and from said container to said bellows;and said container being constantly positively operatively connected tothe wall of said bellows; and a compression spring arranged above andconnected to the top of said container. the arrangement being such thatevery variation in volume of said bellows causes a volumevariation ofsaid container every volume increase of said container causing oxygen topass from said source of supply to said intermediate container and everyvolume diminution thereof causing oxygen to be a forced from saidcontainer into said bellows in an amount which is a constant uniformpercentage of the air respirated and the pressure of the oxyleveroperatively connected to said bellows and tosaid container for thepurpose of transmitting the movement of said bellows to saidintermediate container, whereby each expansion and contraction of saidbellows causes alternately the evacuation of one side and thesimultaneous filling of the other side of said container.

CARL VON HOFF.

